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  #1  
Old 10-26-2006, 09:06 AM
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Disc vs. Drum Brakes

Common knowledge says disc brakes are better, and there's obviously a great deal of truth to that since manufacturers have been moving away from drums slowly but steadily over the years. The problem is, short of having a skidpad, the difference isn't so obvious to me in real-world use. Can anyone point out exactly what makes the disc setup superior?

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  #2  
Old 10-26-2006, 09:15 AM
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Quote:
Originally Posted by gmercoleza View Post
Common knowledge says disc brakes are better, and there's obviously a great deal of truth to that since manufacturers have been moving away from drums slowly but steadily over the years. The problem is, short of having a skidpad, the difference isn't so obvious to me in real-world use. Can anyone point out exactly what makes the disc setup superior?
Ever try and change drum brakes? That alone makes discs worth it.

I'll let someone else tackle the biomechanics/physics of it. Here's an article -

http://www.edmunds.com/ownership/techcenter/articles/43857/article.html
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Old 10-26-2006, 09:19 AM
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Discs are superior in wet weather as well. Heat dispersion is probably the main advantage, so brake fade isn't as much of an issue.

As far as physics is concerned, spin a bicycle tire really fast...which stops it faster, pushing your hand against the tread, or clamping your hand on each side of the rim?
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  #4  
Old 10-26-2006, 09:21 AM
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The biggest difference is the disc brakes clamp on both sides of the rotor and the drum brakes only apply friction to one side.

Also the drum brakes have more parts making them a little more trouble to service and more parts to go bad.

Danny
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  #5  
Old 10-26-2006, 09:26 AM
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Quote:
Originally Posted by Zeus View Post
Ever try and change drum brakes? That alone makes discs worth it.

I'll let someone else tackle the biomechanics/physics of it. Here's an article -

http://www.edmunds.com/ownership/techcenter/articles/43857/article.html
Great article. BRAKE FADE is the concept I was after and explains it all - thanks a bunch!

I've done plenty of drums, so the physical attributes are pretty obvious to me.
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  #6  
Old 10-26-2006, 09:44 AM
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The manufacture of drum brakes on new products should be banned world wide.
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  #7  
Old 10-26-2006, 10:02 AM
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Quote:
Originally Posted by gmercoleza View Post
Common knowledge says disc brakes are better, and there's obviously a great deal of truth to that since manufacturers have been moving away from drums slowly but steadily over the years. The problem is, short of having a skidpad, the difference isn't so obvious to me in real-world use. Can anyone point out exactly what makes the disc setup superior?
You kidding??!! Drive a car with drum brakes through a deep puddle and then hit the brakes. You won't even be able to stop!! Don't ask me how I know this!

Drum brakes get hotter and fade quicker, too.

In a panic stop, disc brakes are more certain to stop the car much faster.
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  #8  
Old 10-26-2006, 10:20 AM
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Originally Posted by G-Benz View Post
Discs are superior in wet weather as well. Heat dispersion is probably the main advantage, so brake fade isn't as much of an issue.

As far as physics is concerned, spin a bicycle tire really fast...which stops it faster, pushing your hand against the tread, or clamping your hand on each side of the rim?
..or C. The tree
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  #9  
Old 10-26-2006, 12:27 PM
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Originally Posted by 123c View Post
I think it's mostly trucks that still use drums in the rear...
No only Toyota gets away with it.

Real world? My budy has a GMC 2500 with discs of course. When you need to stop towing a 5k pound boat stuff like that matters!

Drums are only used now because they are a bit cheaper, ie its a wayto cut a couple of bucks out.

Jaguar and Ferrari solved the drum vs disc debate back in the 50's. Enzo Ferrari hated changing things for the sake of change since drums had always worked well. But he hated getting out braked by Jags even more.
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  #10  
Old 10-26-2006, 12:28 PM
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Lastely drive any 1950's car with a totaly stock drum brake set up. They don't stop, they have horrible brakes.
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  #11  
Old 10-26-2006, 12:45 PM
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Actually, my drums all around 1972 International Travelall would stop on a dime. Now, if the engine died and the booster vacuum went away, then you were hosed.
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  #12  
Old 10-26-2006, 02:01 PM
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I've never had the "privilege" of driving an all-drum car. I guess I'm really missing out...
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  #13  
Old 10-26-2006, 02:09 PM
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most low end GM and fords, as well as the asian cars are still using discs front and drums rear from what I can see through the wheel spokes.
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  #14  
Old 10-26-2006, 02:37 PM
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Tractor trailers still use drums, which is interesting. If any vehicle needs good brakes, it would be a 70,000 lb. vehicle (stop and ponder that number for a second) that is out on the road all day, every day. The shoes on tractor trailer brakes are enormous, so you get a lot of surface area pressing against the inside of those drums. They also have several axles, usually 5, contributing to the braking power.
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  #15  
Old 10-26-2006, 03:07 PM
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It's like this, see

Quote:
Originally Posted by gmercoleza View Post
I've never had the "privilege" of driving an all-drum car. I guess I'm really missing out...
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U


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